Lead cutting machine

Abstract

Lead cutting machine for cutting the leads of components mounted on printed circuit boards, this machine including a conveyor mechanism for the boards and a rotating cutting knife fixed on a carriage which is slidably mounted in a horizontal plane and under the path of the boards and which is coupled with the piston of a pneumatically controlled pressurized air cylinder.

We claim: 
     
       1. An apparatus for trimming component leads protruding from a surface of a circuit board, and comprising: means for conveying said circuit board along a line of feed;   cutter means comprising at least one rotary cutting disc having a rotation axis;   means for displacing said cutter means laterally across said line of feed to effect said lead trimming during said conveying, wherein said cutting disc is generally parallel to said circuit board surface during said displacing and trimming; and   means for independently adjusting speeds of said conveying means and said displacing means.   
     
     
       2. Lead cutting machine according to claim 1, characterized in that said cutter means and said driving means are mounted on a displaceable carriage which is slidably mounted on two parallel rods and that said displacement means include a pressurized air cylinder which is mounted in parallel with said rods and the piston of which is coupled with said carriage. 
     
     
       3. Lead cutting machine according to claim 2, characterized in that said piston is coupled with an outer sliding piece displaceable on the cylinder wall of the pressurized air cylinder. 
     
     
       4. Lead cutting machine according to claim 1, characterized in that said cutter means comprises a cutting disc a cutting edge of which is located in an upper face of the disc. 
     
     
       5. Lead cutting machine according to claim 1, characterized in that said cutter means comprises a cutting disc mounted on an axle and that said driving means comprise a motor having a shaft which is coupled with said axle. 
     
     
       6. Lead cutting machine according to claim 2, characterized in that said adjusting means comprise a cam mounted on said carriage and end-of-stroke switches cooperating with said cam, the position of said switches being adjustable and said switches forming part of a pneumatic control circuit for said pressurized air cylinder. 
     
     
       7. Lead cutting machine according to claim 6, characterized in that said pneumatic control circuit includes two pneumatic first monostable valves which constitute said end-of-stroke switches and control a pneumatic first bistable valve which itself controls two pneumatic second monostable valves which control supply and exhaust of pressurized air to and from cylinder chambers of the cylinder. 
     
     
       8. Lead cutting machined according to claim 7, characterized in that said pneumatic control circuit further includes two pneumatic push-button controlled third monostable valves which also control said pneumatic second monostable valves, and that there is further provided a pneumatic push-button controlled second bistable valve to selectively prepare operation either of the pneumatic bistable valve or of the pneumatic third monostable valves. 
     
     
       9. Lead cutting machine according to claim 8, characterized in that speed regulating valves are mounted between said first monostable valves and said pressured air cylinder. 
     
     
       10. Lead cutting machine according to claim 1, characterized in that an evacuation conveyor belt is mounted below a trajectory of the displacement means, said conveyor belt being adapted to evacuate cut lead waste to a waste bin. 
     
     
       11. Lead cutting machine according to claim 10, characterized in that shield plates are mounted around the trajectory of the displacement means and delimit at their lower end an opening below which said evacuation conveyor belt is mounted. 
     
     
       12. Lead cutting machine according to claim 5, characterized in that said motor, said rods and said pressurized air cylinder are separated from said cutter means by a shield cap. 
     
     
       13. Lead cutting machine according to claim 1, characterized in that other adjusting means are provided to adjust a height of said cutter means with respect to a trajectory of said conveying means. 
     
     
       14. Lead cutting machine according to claim 1, characterized in that said conveying means includes a pair of parallel running chains between the links of which flanges of carriers of said board are removably secured, that said chains are located during at least part of said conveying in wear resistant members, and that said flanges are pressed against said wear resistant members by resilient pressure pieces. 
     
     
       15. An apparatus as in claim 1, and further comprising: means for guiding said cutter means during said displacing, and   means for adjustably setting limits of said displacing.   
     
     
       16. An apparatus as in claim 1, wherein said cutter means displacing is in a direction substantially perpendicular to said line of feed. 
     
     
       17. An apparatus as in claim 1, and further comprising: means for grinding said cutter means, said grinding means located outside a feed path of said circuit board; and   means for controlling said displacing means such that said cutter means is positionable relative to said grinding means for said grinding, upon command.